JP2003066203A - Method for forming fine rugged structure, and member having the ruggedness - Google Patents

Abstract

PROBLEM TO BE SOLVED: To form a fine ruggedness at a low cost for the purposes of antireflection, water repellency, heat radiation and adhesion and in particular, to provide a method for forming the ruggedness having the antireflection effect without any wavelength dependence, and to provide a member having the ruggedness. SOLUTION: The method for forming the fine ruggedness at random on a substrate includes a step of forming an organic compound film on the surface of the substrate and a step of etching the organic compound film.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a method for forming a fine uneven structure on the surface of a substrate. The concavo-convex structure formed by the present invention can be used for applications such as an antireflection portion, a water repellent portion, a heat dissipation portion, and an adhesive portion, and is used as an optical element such as a diffraction element, a lens, a prism, a mask, a mobile phone, a mobile phone It can be applied to a display window of a display device such as an information terminal (PDP), a computer and a television.

[0002]

2. Description of the Related Art A non-glare treatment (AG: A) has hitherto been used as a method for obtaining an antireflection effect due to reflection (external light) of the background of a display (base) and an optical element (base).
anti-glare) and antireflection treatment (AR (Anti
-Reflective) has been proposed.

However, in the non-glare processing, the size of the unevenness is made larger than the wavelength of the visible light region, and the reflected image is scattered by the scattering of light to blur the outline (forms a so-called antiglare effect).
However, there is a problem that a high resolution cannot be obtained because the outlines of characters and images that are information are blurred.

On the other hand, among the antireflection treatments, the one having the antireflection effect by the optical interference action between the respective layers due to the multilayer film structure in which the low refractive index member and the high refractive index member are laminated alternately on the transparent member is a multilayer film. The refractive index and thickness of each thin film of
It is necessary to control with high precision by a film forming means such as vapor deposition, plasma CVD, spin coating, sol-gel, etc., which causes a problem of lowering the yield and increasing the cost. In particular,
Wavelength range 400nm-700nm, 300nm-900
As the thickness increases, the number of layers in the multilayer film increases, which complicates the manufacturing process and further lowers the yield. In addition, since the quality of the film formed by sputtering tends to become porous, adsorption of water etc. will start with standing for a long time, and the reflectance will increase with the passage of time in a specific wavelength range, and the stability of the antireflection effect will be improved. There is also the problem of being low.

Therefore, in the thickness direction of the substrate, wavelengths in the visible light range
The unevenness is smaller than that, and the refractive index is continuous in the thickness direction.
Attention has been paid to a method of changing the distribution to obtain an antireflection effect.
There is. There are various methods for forming the unevenness,
For example, the method of making the surface porous, the method of forming pores on the surface
There is a method, for example, HF, HF-CH on the transparent substrate surface _Three
COOH, HCl, HNO_Three-Wet with a chemical such as HCl.
There is a method of forming the unevenness on the surface by etching. Well
In addition, several hundreds on the plastic surface by caustic soda treatment
Method of forming rough asperities of um diameter, spraying abrasive
Sand blasting method to make unevenness, silica solution (silicon
・ In alkoxide alcohol solution _TwoO_Three; Sn
(Conductive filler such as tin-containing indium oxide)
The powder is mixed and dispersed on a transparent member by the spray method.
Baking is baked at 150 to 200 ° C to form conductive irregularities.
A method of doing so has also been proposed.

[0006]

However, it is difficult for the conventional method of forming unevenness to form unevenness smaller than the size of the wavelength in the visible light region.

On the other hand, published patent 2000, 25th
Japanese Patent No. 8607 proposes a method in which an island-shaped metal film having a thickness of 1 nm to 10 nm is formed on the surface (base body) of a transparent member by sputtering or vapor deposition and fine irregularities are formed by plasma etching. However, according to this method, in order to form an island-shaped metal film by sputtering or vapor deposition, the film formation time must be controlled within an unstable time of plasma discharge start, that is, within a few seconds to 10 seconds. However, it is difficult to control the island-shaped film thickness and diameter with good reproducibility. Further, the film thickness cannot be made as thick as 1 nm to 10 nm in order to form the island structure, and the mask does not function sufficiently.

It is also conceivable to form fine irregularities by using photolithography in a semiconductor process. In this method, for example, a fine mask is formed on the surface of the base by photolithography, and the base is dry-etched to form irregularities. In this method, if the selection ratio (etching rate ratio) between the mask and the object is 10 or more, the height of the unevenness can be deepened to about 0.3 μm to 1 μm, but the height of the unevenness is constant. There is a problem that an antireflection effect is obtained for a specific wavelength, but not for another wavelength. More specifically, if there is no distribution in the height of the unevenness, for example, the refractive index change between the refractive index of the substrate of 1.5 and the refractive index of 1.0 of the air in contact with the substrate is linear, and the gradual refractive index is low. No change can be obtained, visible light range 400
In the range of nm to 700 nm, a sufficient reflectance preventing effect cannot be obtained. Further, in order to form a fine mask of 300 nm to 1000 nm, an expensive reduction projection type device (stepper) or electron beam drawing device must be used, which is expensive and impractical. Further, the electron beam drawing apparatus has a small beam diameter and is not suitable for drawing a large area.

[0009] In Japanese Patent Laid-Open No. 239501/1989, a plastic surface substrate is roughened by high-frequency plasma treatment so as to have an average roughness of 0.05 um to 5 um, and then MgF _{2 is formed} on the rough surface. , SiO ₂ , Na ₃ A
It proposes a method of forming an antireflection layer such as 1F ₆ and CaF ₂ in a thickness of about 70 nm to 120 nm in consideration of light interference conditions. However, the method height alone is uneven high frequency plasma treatment of the substrate of the plastic surface (depth) is insufficient at most obtain the antireflection effect by about 0.5 [mu] m, and an antireflection film of MgF ₂ or the like Configuration is required.

Further, a method of applying a binder to the substrate and then adsorbing the fine particles, and a method of plasma etching the fine particles adsorbed by the binder are also conceivable. However, these methods have the same problem as non-glare processing because particles are easily adsorbed to each other, coarse irregularities are formed, and light is scattered. Further, it is difficult to obtain a sufficiently deep unevenness of about 0.3 μm to 1 μm, and the antireflection effect is insufficient. Therefore, an antireflection film such as a MgF ₂ film is sputtered on the uneven surface, It had a structure formed by vapor deposition.

Therefore, the present invention is a method of forming fine unevenness at low cost for applications such as antireflection, water repellency, heat dissipation, and adhesion, and in particular, a method of forming unevenness in which the antireflection effect has no wavelength dependence, It is an object to provide a member having the unevenness.

[0012]

In order to achieve the above object, a method of randomly forming fine irregularities on a substrate of the present invention comprises a step of forming a film of an organic compound on the surface of the substrate, Etching the film of the organic compound. Random unevenness includes both the case where unevenness of the same height (depth) is arranged at random and the case where unevenness is formed at random height (depth) and pitch. From the experience of the present inventors, the random unevenness has no wavelength dependence when applied to the antireflection portion. Also,
Since etching is performed through the organic compound film, finer unevenness can be formed as compared with the case where the organic compound film is not used.

To form random unevenness, for example,
The forming step locally makes the film thickness of the organic compound film nonuniform, and the etching step locally makes the etching rate nonuniform. In the former case,
In the forming step, for example, the film forming rate of the organic compound film is locally nonuniform.

Etching may be wet or dry. The surface of the substrate may be flat or not flat, and is applicable to a case where the surface of the substrate is a curved surface or a case where unevenness is already formed on the surface. The forming step may include, for example, plasma CVD, spin coater,
The film of the organic compound is formed by using one of a spray method and a vapor deposition method.

By controlling the film thickness of the organic compound film, the etching time, and / or the number of times of repeating the forming step and the etching, the height of the unevenness is 30 nm to 5 μm, and if necessary, 50 nm to 1000 nm, and / or the pitch of the irregularities is 50 n
It may further have a step of controlling from m to 1200 nm. For example, the height of the unevenness is 50 nm to 1000 n
If m and pitch are set to 50 nm to 1200 nm,
The antireflection film as disclosed in Japanese Patent Laid-Open No. 239501/1989 becomes unnecessary. This range of height can be applied to the antireflection portion, the heat radiation portion, the adhesive portion, and the water repellent portion applicable to a wide wavelength range. Note that the present invention does not exclude other control elements (for example, the concentration of chemicals used for wet etching).

A member according to another aspect of the present invention is a base and a member formed on the base and having a height of 30 nm to 5 μm.
Or a film of an organic compound formed on the surface thereof, or alternatively, a substrate having a surface formed with random unevenness having a height of 30 nm to 5 μm. Such a member can also have the same effect as the above method.
If necessary, the height of the irregularities is 50 nm to 1000.
nm, the pitch of the irregularities is 50 nm to 1200 nm
Is set to. Further, it is preferable that the height and / or pitch distribution of the irregularities is not uniform. The nonuniformity means the above-mentioned randomness, and an antireflection effect that does not depend on a specific wavelength can be achieved. Such a substrate is a lens,
Optical elements such as prisms and masks, mobile phones, PHS,
It can be applied to a display window of a display device such as a PDA, a PDP, a personal computer and a television. Further, the irregularities function not only as an antireflection portion but also as a water repellent portion, a heat radiation portion, and an adhesive portion.

According to still another aspect of the present invention, there is provided a molding method, which comprises a step of forming a film of an organic compound on the surface of the substrate, and the film of the organic compound is etched to have a height of 50 nm to 1000 nm on the substrate. And the pitch is 50n
randomly forming irregularities of m to 1200 nm, forming a conductive film on the surface of the irregularities,
The method includes the steps of electrolytically plating a metal with the conductive film as a cathode to form a stamper, and mounting the stamper on a mold and injecting a resin using the mold. By using the injection molding method, the above-mentioned display unit and the like can be manufactured at low cost.

A molding method according to still another aspect of the present invention is a step of forming a film of an organic compound on the surface of the substrate, and etching the film of the organic compound to have a height of 50 nm to 1000 nm on the substrate. And the pitch is 50n
The method includes the steps of randomly forming unevenness of m to 1200 nm, and the step of introducing a molten resin to the surface of the unevenness and transferring the uneven structure to the resin.

Other objects and further characteristics of the present invention will become apparent from the embodiments described below with reference to the accompanying drawings.

[0020]

BEST MODE FOR CARRYING OUT THE INVENTION Embodiments of the present invention will be described below with reference to the accompanying drawings.

As a result of diligent studies of the problems of the prior art, the inventors of the present invention form an organic compound film (hereinafter referred to as “organic compound film”) on the surface of a substrate and then etch the organic compound film. As a result, it was discovered that desired fine and random irregularities are formed on the surface of the substrate.

As the base material, a material of a portion where it is desired to exert various effects including an antireflection effect, a water repellency effect, a heat dissipation effect and an adhesive effect is selected. Anti-reflection is achieved by forming irregularities smaller than the target wavelength range (visible light, infrared light, ultraviolet light, etc.) in the thickness direction of the substrate and continuously changing the refractive index distribution in the thickness direction. To do. Water repellency is achieved by forming finer irregularities than water, oil, solution or other liquid molecules to prevent adsorption of liquid molecules. The heat dissipation is achieved by forming irregularities on the surface of the substrate and increasing the area of the heat dissipation surface. Bonding is achieved by forming irregularities on the substrate and increasing the bonding area. In the present invention, the size of the unevenness can be adjusted according to the effect desired to be exerted by the unevenness, but the antireflection effect will be described below as an example.

When it is desired to exert the antireflection effect, the substrate is provided with an optical element such as a lens, a prism, a mask or the like, or a light-transmitting material constituting a display device such as a mobile phone, a PHS, a PDA, a computer or a television ( Quartz, glass, plastic, etc.) are selected. However, when transferring to a stamper as in Example 3 described later, silicon or another material can be selected for the substrate.

In this embodiment, the surface of the substrate is flat.
To flatten the surface of the substrate, CMP (Chemical
Various planarization techniques such as Mechanical Polisher) can be used. However, the present invention can use not only flat substrates but also non-flat substrates. Therefore, the surface of the substrate is curved,
Irregularities may already be formed on the surface of the substrate.

Next, as shown in FIG. 1, an organic compound film is formed on the substrate. Here, FIG. 1 is a cross-sectional view showing a state in which the organic compound film 20 is formed on the substrate 10. One of the methods of controlling the dimensions (that is, the height (depth) and the pitch) of the unevenness is a method of controlling the film thickness t of the organic compound film 20. The reason why the organic compound film 20 is stacked and then etched is that it is easier to form fine irregularities than when the substrate 10 is directly etched.

The organic compound film is formed, for example, by plasma CVD,
It can be formed by a spin coater, a spraying method, a vapor deposition method, or another method. The organic compound is, for example, polytetrafluoroethylene (Teflon (registered trademark)).

In addition, a small amount of carbon, hydrogen, fluorine and oxygen
In a method for producing an organic compound film containing at least one kind
C_xH_yF_zSystem gas, C that does not contain hydrogen_XF_ySystem flow
Robocarbon-based gas and hydrocarbon gas containing no fluorine
A hydrogen atom of a hydrocarbon chain, chain or alicyclic hydrocarbon to a hydroxyl group O
H-substituted hydroxy compounds or aromatic hydrocarbon nuclei
Aromatic Hydroxy Compounds Having Hydrogen Substituted by Hydroxyl Group
And especially CF_Four, C_TwoF ₆, CHF_Three, CH_TwoF_Two, C
H_ThreeF, C_TwoF_Four, C_ThreeF₈, C_FourF₈, C_TwoF _Four, C
_xH_y(However, x and y are x ≧ 1, y ≧ 2), methylalco
With at least one type of alcohol and ethyl alcohol
Organic compounds may be used.

Further, an organic silicon compound containing silicon in the organic compound may be used, for example, hexamethyldisiloxane, hexamethyldisilazane, tetramethylsilane, hexamethylcyclotrisilazane, diethylaminotrimethylsilane, trimethylvinylsilane, tetramethoxysilane. There is an organic silicon compound containing at least one of the above.

Next, the substrate 10 is etched from above the organic compound film 20. The etching forms fine irregularities and also irregularities at random. The reason for making the unevenness fine is to exert the antireflection effect in the present embodiment, and the reason for making the unevenness random is to eliminate the wavelength dependence of the antireflection effect in the present embodiment. The miniaturization and randomization can be performed by controlling only the etching process (for example, by controlling the etching time), but as described above, by other control elements such as controlling the film thickness of the organic compound film. Alternatively, it can be carried out in cooperation with this.

In the present embodiment, "random unevenness" means
Although the height (depth) and the pitch of the unevenness are random, the present invention also includes the case where only the height (depth) of the unevenness is random or the pitch of the unevenness is random. When only the height (depth) of the irregularities is random, for example, when the irregularities of different heights (depth) are arranged at a constant pitch, and when only the pitch of the irregularities is random For example, it is a case where irregularities having the same height (depth) are arranged in pieces.

The etching may be finished in a state where the unevenness 30a is formed on the organic compound film 20 as shown in FIG.
As shown in FIG. 3, the final state may be the state in which the unevenness 30b is formed on the base body 10. Here, FIG. 2 is a sectional view of the substrate 10 having the etched organic compound film 20a, and FIG. 3 is a sectional view of the etched substrate 10a. The reference numbers 10, 20 and 30 collectively refer to the reference numbers 10a, 20a, 30a and 30b unless otherwise specified.

The etching may be dry etching such as plasma etching or wet etching using chemicals. The case of using plasma etching will be described later.

Here, the height and depth of the unevenness 30 are shown in FIG.
Will be described with reference to. Here, FIG. 4 is a cross-sectional view for explaining the height and the depth of the unevenness 30. In the present embodiment, the depth of the valley P ₂ is, for example, the depth from P ₁ ,
The height of the mountain P _{3 is} the height from P ₂ . However, in another embodiment, the distance from a certain reference position is set as the unevenness 30.
Can be defined as the height and depth of the.

The random unevenness 30 eliminates the wavelength dependence of the antireflection effect and facilitates exerting the antireflection effect in a wide wavelength range instead of a specific wavelength. Although the reason for this is not clearly understood, the inventors of the present invention believe that the substrate 10 having the random unevenness 30 has an advantage that the change in the refractive index between the air and the fine unevenness 30 is moderate. thinking.

The shape of the fine unevenness 30 is close to a conical shape, and as shown in FIG. 5, the area of the existing unevenness is smaller as the height from the base 10 is higher. Here, FIG. 5 shows fine irregularities 3.
FIG. 10 is a schematic cross-sectional view for explaining how 0 occupies the area in the height direction H. As shown in FIG. 5, when the fine concavo-convex 30 close to a conical shape when viewed from above is cut along planes H ₁ , H ₂ and H ₃ perpendicular to the height direction H, the concavo-convex 30 present on a higher plane is It will be appreciated that the cross section will be smaller.

Therefore, the average refractive index is as follows:
It is considered that the volume gradually changes in the opposite direction (that is, in the depth direction) and gradually increases. Since the refractive index of air is about 1 and the refractive index Ns of the unevenness 30 is larger than 1, the average refractive index becomes smaller as the height becomes higher and becomes closer to Ns as the height becomes lower, as shown in FIG. Be understood. Here, FIG. 6 is a graph showing the relationship between the height of the unevenness 30 and the average refractive index.

According to the simulation result of the optical interference of the multilayer film in which the layer in the direction perpendicular to the substrate is divided into 500 and the refractive index of each layer is changed stepwise, the refractive index of the first layer, that is, the tip of the unevenness is It is known that the smaller the value, that is, in FIG. 6, the smaller the average refractive index changes from the linear change indicated by the dotted line to the gradual change indicated by the arrow, the smaller the reflectance.

The change in average refractive index during plasma etching will be described with reference to FIG. Here, FIG.
It is a schematic sectional drawing which shows the change of the unevenness | corrugation 30 during plasma etching, and FIG.7 (b) is the top view. Plasma etching proceeds from the high unevenness 30 to FIG.
It is understood that since the unevenness 30 is changed as shown by the arrows in FIGS. 6A and 6B, the average refractive index is changed by the plasma etching in the direction shown by the arrow in FIG.

As described above, the unevenness 30 of the present embodiment does not have a uniform distribution of height and depth. The non-uniformity of the etching rate of the organic compound film and the non-uniformity of the film thickness of the organic compound can be controlled by adjusting the pressure, gas concentration, gas flow rate, input power, substrate temperature, vacuum chamber temperature, vacuum chamber dimension, etc. Can be controlled. Since the height and depth distribution of the unevenness 30 is non-uniform, the average refractive index changes gently, and an antireflection effect can be obtained over a wider wavelength range than a base having a uniform unevenness height. It is thought to be possible.

Further, the unevenness 30 of the present embodiment is similarly
The pitch distribution is also not uniform. The non-uniformity of the etching rate of the organic compound film and the non-uniformity of the film thickness of the organic compound can be controlled by adjusting the pressure, gas concentration, gas flow rate, input power, substrate temperature, vacuum chamber temperature, vacuum chamber dimension, etc. Can be controlled. Since the pitch distribution of the unevenness 30 is non-uniform, it is considered that the average refractive index changes gently, and the antireflection effect can be obtained over a wider wavelength range than that of a substrate having a uniform unevenness pitch.

For the antireflection effect, the dimension of the unevenness is preferably 1/3 or less of the wavelength of visible light. For example, the depth (height) of the unevenness 30 is 1000 nm or less, and the pitch of the unevenness is 800.
nm or less is good. Considering that the present invention obtains an effect other than antireflection, the height of the unevenness 30 is 30 nm.
To 5 μm, if necessary, 50 nm to 1000 n
The pitch of m and the unevenness 30 can be applied to 50 nm to 1200 nm. For example, the height of the unevenness is 50 nm to 10 nm.
When the thickness is set to 00 nm and the pitch is set to 50 nm to 1200 nm, the antireflection film disclosed in Japanese Patent Laid-Open No. 239501/1989 becomes unnecessary.

The present inventors have discovered that the depth and pitch of the unevenness can be controlled by controlling the number of pairs of the organic compound film forming step and the etching step. If the number of etching steps is set to 2 or more, for example, the depth of the unevenness is 1000 nm or less and the unevenness pitch is 8
It can be adjusted to 00 nm or less. If the pitch of the unevenness is large, smoke is generated on the display window substrate of the display and the visibility of information such as characters is deteriorated. In principle, the antireflection effect of randomly forming fine irregularities is that the irregularity pitch and depth are about 1/3 or less of the shortest wavelength compared to the multilayer film stacking method using multiple interference. It has only to be designed, and has an excellent feature that an antireflection effect can be obtained over a wide wavelength range with a simple structure. Note that, as described above, the height (depth) and pitch of the unevenness can be controlled also by the time of each etching process.

According to the method for forming fine and random unevenness on the substrate of the present invention, an expensive photolithography apparatus,
It is possible to provide a substrate on which fine irregularities having an antireflection effect are formed by a method with a low manufacturing cost, without requiring highly accurate control by a sputtering device or a vapor deposition device.

Further, according to the manufacturing method of the present invention, the concave and convex structure is transferred to the stamper, and the molded product is mounted on the mold and injection-molded, so that the molded product can be reproduced in large quantity at low cost. Can be lowered.

The reason why the method of the present invention can form fine irregularities 30 on the surface of the substrate 10 is that the organic compound film 20.
Unevenness 3 on the surface of the organic compound film 20 when etching
It is considered that 0 is induced and this is transferred to the surface of the substrate 10. The reason why the unevenness 30 is formed on the organic compound film 20 is considered to be shrinkage due to thermal heating by plasma in the case of dry etching, and damage to the film of the organic compound due to heat generation due to chemical reaction in the case of wet etching such as KOH. It is considered that since the stress of the organic compound film is released during the etching, the unevenness 30 is formed on the surface of the organic compound film 20, and the unevenness 30 is transferred to the surface of the substrate 10. In the case of a plasma polymerized film, it is considered that fluorine in the polymerized film becomes a radical due to ion bombardment during plasma etching, passes through the organic compound film 20, and reacts with the surface of the substrate 10 to form irregularities 30. In any case, it is considered that the existence of multiple mechanisms is caused by the films of various organic compounds.

[0046]

Example 1 Inductively coupled plasma (I
CP: Inductively Coupled Pla
sma) Using the etching apparatus 100, the object 150 to be processed as the structure shown in FIG. 1 was etched. IC
The P etching apparatus 100 etches the surface of the target object 150 by generating a chemically active reactive species in plasma. Here, FIG. 8 is a schematic sectional view of the ICP etching apparatus 100.

The ICP etching apparatus 100 comprises a high frequency power supply 110 and a plasma source power supply upper coil 120.
, The quartz plate 130, the reactor 140, and the object to be processed 15
0, a susceptor 160, a lower electrode 170, and a bias power supply 180. It should be noted that other devices such as a matching box are omitted in FIG.

The high frequency generated by the high frequency power supply 110 is introduced into the reactor 140. The quartz plate 130 functions as a transmission window that transmits high frequencies. In the reactor 140,
A gas supply system (not shown) for supplying C ₄ F ₈ gas which is a reaction gas is connected. The gas supply system includes a gas source, a valve, and a flow rate control device, and in this embodiment, introduces 10 cc. Further, the reactor 140 is connected to an exhaust device (not shown) such as a vacuum pump and the internal pressure is set to 1 Pa.

The reactor 140 is made of a conductor such as aluminum, and has a cylindrical shape as an example in this embodiment. Inside the reactor 140 is a susceptor 160.
And the lower electrode 170 are arranged, and the object 150 is supported on the susceptor 160 by a clamp mechanism (not shown) or the like. The susceptor 160 controls the temperature of the object 150 in the reactor 140.

The reaction gas is turned into plasma by the upper coil 120, the lower electrode 170, the bias power source 180 and the high frequency, and becomes radical ions having strong activity, which react with the object 150 to be processed to perform film formation or etching.

In this embodiment, the upper coil 120 has 20
The applied electric power of 0w was applied, and the applied electric power of the bias to the lower electrode 170 was set to 0w. The temperature of the lower electrode 170 is 19
Was set to ° C. Silicon was used for the substrate (substrate) of the object 150 to be processed.

Under the above conditions, the bias generated on the substrate is estimated to be about the plasma potential (10 eV or less). With this bias, a Teflon-like plasma polymerized film is formed on the substrate rather than etching the substrate itself. The film thickness was about 185 nm after 4 minutes of forming the polymer film.

Next, the object to be processed 1 was treated with the O ₂ / CF ₄ mixed gas in the same reactor 140 without taking out the object to be processed 150.
50 was dry-etched. The etching condition is CF ₄
The gas is 75 sccm, the O ₂ gas is 60 sccm, the reaction pressure is 3 Pa, the etching time is 10 minutes, the input power to the upper coil 120 is 500 w, the input power to the object 150 side is 100 w, and the object 150 temperature is 19 ° C. Set.

After the treatment, the surface of the substrate was observed by SEM (secondary electron microscope) and AFM (atomic force microscope). As a result, it was confirmed that fine irregularities were formed on the surface of the substrate. The uneven structure has an uneven depth (height) of about 600 nn.
It was m to 500 nm and the width was 500 nm to 200 nm.
Next, in order to transfer the fine unevenness of the substrate to the stamper,
Ni is deposited on the uneven surface of the substrate with a vapor deposition device to a thickness of about 500 nm.
It was vapor-deposited. Before vapor deposition, the organic compound on the surface of the silicon substrate was removed by oxygen plasma. Next, a thickness of about 300 μm was formed in an electrolytic Ni plating bath. The electrolytic plating conditions are: nickel sulfamate plating solution 200 g / liter, pH 4.0, bath temperature 45 ° C., cathode current 1 to
3A. Next, this mold was attached to an injection molding machine, and a polycarbonate substrate having fine irregularities was obtained by injection molding. A spectrophotometer (Hitachi U-3
As a result of measurement at 410), wavelength 400 nm to 750 nm
The reflectance in the region was 0.5% or less (FIG. 9).

In this embodiment, CF is used for dry dry etching.
_Although a mixed gas of ₄ and O ₂ was used, the gas species is not limited as long as the organic compound film can be removed, and SF ₆ , CHF ₃
CFC-based gas such as, fluorocarbon-based gas, CO ₂ ,
A gas such as CO or N ₂ may be used. In wet etching, KOH, NAOH, NH ₄ OH, H ₂ S
O ₄ , H ₂ O _{2 and the} like can be used, but are not limited thereto.

[0056]

Second Embodiment In the ICP etching apparatus 100, similarly,
10 cc of C ₄ F ₈ gas was introduced, and the reaction pressure was set to 1 Pa.

The applied power of 200 w was applied to the upper coil 120, and the applied power of bias to the lower electrode 70 was 0 w. The temperature of the lower electrode 170 was set to 19 ° C. Silicon was used as the substrate (substrate). The silicon substrate was placed on the lower electrode.

Under the above conditions, the bias generated on the substrate is estimated to be about the plasma potential (10 eV or less). With this bias, a Teflon-like plasma polymerized film is formed on the substrate rather than etching the substrate itself. The film thickness was about 185 nm after 4 minutes of forming the polymer film. The step of forming a polymerized film on this substrate is hereinafter referred to as "A" step. Next, without taking out the substrate, the substrate was dry-etched with an O ₂ / CF ₄ mixed gas in the same chamber. The etching conditions are as follows: CF ₄ gas 75 sccm, O
₂ gas was 60 sccm, reaction pressure was 3 Pa, etching time was 10 minutes, input power to the upper coil was 500 w, input power to the substrate (base) side was 100 w, and substrate temperature was set to 19 ° C. The step of dry-etching the substrate through the polymer film on the substrate is hereinafter referred to as "B" step. The schematic diagrams of the steps are as shown in FIGS.

Next, when the step A and the step B were repeated 2 to 100 times, it was found that the size of the fine irregularities was reduced depending on the number of repetitions. The evaluation was performed by SEM (secondary electron beam scanning microscope) and atomic force microscope AFM.
Further, the unevenness information obtained by the AFM was statistically analyzed for the maximum pitch and the maximum depth of the unevenness by the unevenness image analysis software. Table 1 shows the relationship between the number of repetitions of the "A"-"B" steps, the maximum uneven pitch, and the maximum uneven depth.

[0060]

[Table 1]

Next, the number of repetitions of the "AB" step is set to 5
This was performed 0 times, and in order to transfer the fine irregularities of the obtained substrate to the stamper, Ni was vapor-deposited on the irregular surface of the substrate by a vapor deposition apparatus to a thickness of about 500 nm. Next, a Ni layer having a thickness of about 300 μm was formed in an electrolytic Ni plating bath. The conditions for electrolytic plating are 200 g of nickel sulfamate plating solution
/ Liter, pH 4.0, bath temperature 45 ° C., cathode current 1 to 3 A. Next, this mold was attached to an injection molding machine, and a polycarbonate substrate having fine irregularities was obtained by injection molding. The reflectance of the substrate was measured with a spectrophotometer (UV-3410 manufactured by Hitachi), and the result was that the wavelength was 400 nm to 7 nm.
The reflectance was 0.5% or less in the region of 50 nm.

[0062]

[Third Embodiment] In order to make uneven height distribution uneven,
With an ICP (induction heating type) plasma etching device, C ₄
F ₈ gas was introduced at 15 cc, and the reaction pressure was set to 0.7 Pa. Moreover, the dimension of the vacuum chamber was locally changed to an appropriate one. The applied power of 300 w was applied to the upper coil, and the applied power of bias to the lower electrode was 0 w. The temperature of the lower electrode was set to 15 ° C. Silicon was used as the substrate (substrate). The silicon substrate was placed on the lower electrode.

Under the above conditions, the bias generated on the substrate is estimated to be about the plasma potential (10 eV or less). With this bias, a Teflon-like plasma polymerized film is formed on the substrate rather than etching the substrate itself. The film thickness was about 195 nm after 3 minutes of forming the polymer film. The step of forming a polymerized film on this substrate is hereinafter referred to as "A" step.

Next, the substrate was dry-etched with an O ₂ / CF ₄ mixed gas in the same chamber without taking out the substrate.

In order to make the height distribution of the unevenness uneven,
In the etching, CF ₄ gas was added at 75 sccm and O ₂ was added.
The gas was introduced at 60 sccm, the reaction pressure was 3 Pa, the etching time was 10 minutes, and the input power to the upper coil was 750 w.
Power input to the substrate (base) side is 50w, substrate temperature is 19 ° C
Set to. The step of dry-etching the substrate through the polymer film on the substrate is hereinafter referred to as "B" step. Schematic diagrams of the steps are shown in FIGS.

Next, the number of repetitions of the "AB" step is set to 1
It was performed 00 times, and in order to transfer the fine irregularities of the obtained substrate to the stamper, Ni was vapor-deposited to a thickness of about 500 nm on the irregular surface of the substrate by a vapor deposition device. Next, in the electrolytic Ni plating bath,
The layer was formed to a thickness of about 300 μm. The electrolytic plating conditions are: nickel sulfamate plating solution 200 g / liter, pH 4.0, bath temperature 45 ° C., cathode current 1 to 3.
It was set to A. Next, this mold was attached to an injection molding machine, and a polycarbonate substrate having fine irregularities was obtained by injection molding. The reflectance of the substrate is measured by a spectrophotometer (UV-3 manufactured by Hitachi
As a result of measurement at 410), wavelength 400 nm to 750 nm
The reflectance was 0.5% or less in the region. (Comparative Example) A multilayer film was laminated on a transparent substrate by sputtering. The structure is base / SiN 19 nm / SiO 17.5 n
m / SiN 100 nm / SiO 81 nm. As a result of measuring the obtained reflectance with a spectrophotometer (Hitachi UV-3410), the reflectance was around 1.0% in the wavelength range of 400 nm to 680 nm, but at wavelengths of 680 nm or longer, the reflectance was long wavelength. The higher the reflectance. Again 400
The reflectance of 1 nm or less was 1% or more (FIG. 10).

Thus, due to the optical interference of multiple layers,
It is almost difficult to reduce the reflectance to 1% or less in the short wavelength region of 400 nm or less and the long wavelength region of 740 nm or more.

As described above, in this embodiment, the organic compound film is formed on the surface of the substrate, and the organic compound film is interposed between
Etching was performed using CF ₄ / O ₂ mixed gas or the like (dry etching) or wet etching was performed using KOH or the like (wet etching). Further, by repeating the film formation of the organic compound and the etching process, the uneven pitch was 800 nm or less, the uneven height was 1000 nm or less, and preferably the uneven height and pitch could be made uneven. By appropriately controlling the parameters of the film of the organic compound and the parameters of dry and wet etching, it was possible to randomly form fine irregularities to be formed on the surface of the substrate. Further, Ni was vapor-deposited on the concavities and convexities, and then Ni electroplating was performed to transfer the concavities and convexities to the stamper, and by mounting the stamper on a mold, it was possible to manufacture a large quantity of plastic substrates at a low price.

[0069]

According to the present invention, fine irregularities are inexpensively formed for applications such as antireflection, water repellency, heat dissipation, and adhesion, and in particular, the antireflection effect forms irregularities having no wavelength dependence. A method and a member having the unevenness can be provided.

[Brief description of drawings]

FIG. 1 is a cross-sectional view showing how an organic compound film is formed on a substrate.

FIG. 2 is a cross-sectional view showing a state in which an organic compound film is etched to form irregularities.

FIG. 3 is a cross-sectional view showing a state where fine irregularities are formed on a substrate.

FIG. 4 is a cross-sectional view for explaining the height and depth of unevenness.

FIG. 5 is a schematic cross-sectional view for explaining how the occupied area of the fine and random unevenness of the present invention decreases in the height direction.

FIG. 6 is a graph showing the relationship between the height of fine and random irregularities of the present invention and the average refractive index.

FIG. 7 is a cross-sectional view showing a state where fine irregularities are formed on a substrate.

FIG. 8 is a cross-sectional view for explaining the height and depth of unevenness.

9 is a graph showing the relationship between the wavelength of unevenness and reflectance in Example 1. FIG.

FIG. 10 is a graph showing the relationship between the wavelength of unevenness and the reflectance of the comparative example.

[Explanation of symbols]

10, 10a substrate 20, 20a Organic compound film 30, 30a, 30b unevenness 100 ICP etching equipment

   ─────────────────────────────────────────────────── ─── Continued front page    (72) Inventor Toshinori Sugiyama             Hitachima, 1-88, Torora, Ibaraki City, Osaka Prefecture             Within Kucsel Co., Ltd. (72) Inventor Akihito Sakamoto             Hitachima, 1-88, Torora, Ibaraki City, Osaka Prefecture             Within Kucsel Co., Ltd. F term (reference) 2K009 AA02 BB01 BB11 CC21 DD12                       DD17 EE00 FF03                 4K029 AA09 AA11 BA12 BA62 BB02                       BC07 BD00 CA12 EA01 EA02                       FA05 GA02                 4K030 BA14 BA61 CA06 CA07 DA02                       DA08 FA01 JA01 JA13 LA11

Claims (25)

[Claims] 1. A method for randomly forming fine irregularities on a substrate, the method comprising the steps of forming a film of an organic compound on the surface of the substrate and etching the film of the organic compound. 2. The method according to claim 1, wherein in the forming step, the film thickness of the organic compound film is locally nonuniform. 3. The method according to claim 2, wherein in the forming step, a film formation rate of the organic compound film is locally nonuniform. 4. The method of claim 1, wherein the etching step causes the etching rate to be locally non-uniform. 5. The height of the unevenness is set to 30 by controlling the number of times of repeating the forming process and the etching.
The method according to claim 1, further comprising the step of controlling to nm to 5 μm. 6. The method according to claim 1, further comprising controlling the height of the unevenness to be 30 nm to 5 μm by controlling the etching time. 7. The method according to claim 1, further comprising controlling the height of the unevenness to be 30 nm to 5 μm by controlling the film thickness of the film of the organic compound. 8. The method according to claim 5, wherein the controlling step controls the height of the unevenness to be 50 nm to 1000 nm. 9. The control step controls the pitch of the irregularities to be 50 nm to 1200 nm.
The method according to any one of the above. 10. The method of claim 1, wherein the etching step comprises dry etching. 11. The plasma CV is performed in the forming step.
The film of the organic compound is formed by using any one of D, a spin coater, a spraying method, and a vapor deposition method.
The method described. 12. A member comprising a substrate and an organic compound film formed on the substrate and having random irregularities with a height of 30 nm to 5 μm formed on the surface thereof. 13. A member having a substrate on the surface of which random irregularities having a height of 30 nm to 5 μm are formed. 14. The height of the irregularities is 50 nm to 100.
The member according to claim 12 or 13, which has a thickness of 0 nm. 15. The pitch of the irregularities is 50 nm to 12
The member according to claim 12 or 13, which has a thickness of 00 nm. 16. The member according to claim 12, wherein the distribution of the height of the unevenness is non-uniform. 17. The member according to claim 12, wherein the pitch distribution of the unevenness is non-uniform. 18. The member according to claim 12, wherein the base body constitutes an optical element. 19. The substrate constitutes a display window.
The member according to 2 or 13. 20. The unevenness is an antireflection portion.
The member according to 2 or 13. 21. The member according to claim 12, wherein the unevenness is a water repellent portion. 22. The member according to claim 12, wherein the unevenness is a heat dissipation portion. 23. The member according to claim 12, wherein the unevenness is an adhesive portion. 24. A step of forming a film of an organic compound on the surface of the substrate, wherein the film of the organic compound is etched to form irregularities on the substrate having a height of 50 nm to 1000 nm and a pitch of 50 nm to 1200 nm. And forming a conductive film on the surface of the unevenness, forming a stamper by electroplating a metal using the conductive film as a cathode, and mounting the stamper on a mold to attach the mold. And a step of injection-molding a resin by using. 25. A step of forming a film of an organic compound on the surface of the substrate, wherein the film of the organic compound is etched to form irregularities having a height of 50 nm to 1000 nm and a pitch of 50 nm to 1200 nm on the substrate. And a step of introducing a molten resin into the surface of the unevenness and transferring the uneven structure to the resin.